JPH05268691A - Microphone device - Google Patents

Abstract

PURPOSE:To incorporate the microphone device to a device having a vibration source in its inside by providing plural omnidirectional microphones, HPFs, phase shifters, subtractors, equalizers and variable amplifiers to the device and mixing outputs of prescribed variable amplifiers. CONSTITUTION:The omnidirectional microphones 1, 2 are connected respectively to HPFs 4, 5 and the omnidirectional microphones 3, 4 are connected respectively to phase shifters 7, 8. Then subtractors 9, 10 subtract an output of the phase shifter 7 from outputs of the HPFs 1, 2, and a subtractor 11 subtracts an output of the phase shifter 8 from an output of the omnidirectional microphone 4. Then equalizers 12, 13, 14 equalize outputs the subtractors 9, 10, 11 and an HPF 15 cuts off a low sound frequency of the equalizer 14. A variable amplifier 18 is used to vary the output of the HPF 15 and variable amplifiers 16, 17 are used to vary the outputs of the equalizers 12, 13. Outputs of the amplifiers 16, 18 are mixed by a mixer 21 and outputs of the amplifiers 17, 18 are mixed by a mixer 22. Then the microphone device is incorporated to a device having a vibration source in the inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone device capable of collecting sound in accordance with an image by interlocking with a zooming mechanism such as a video camera or an 8 mm camera, and is particularly incorporated in a device having a noise source or a vibration source inside. The present invention relates to a microphone device.

[0002]

2. Description of the Related Art In recent years, in order to integrate video and audio for video integrated cameras and 8 mm cameras,
A microphone device capable of collecting a zoom in synchronization with an image has been developed. There are two types of conventional microphone devices, a monaural type and a stereo type.

The former monaural type microphone device changes the sound collection angle of the microphone according to the angle of view of the camera, and is based on the technique of changing the directivity pattern. It is realized by synthesizing the output of the microphone. In addition, in order to enhance the zoom effect, a method of increasing the sensitivity from a wide angle to a telephoto is generally used (for example, Japanese Patent Publication No. 59-101).
19). To get a good zoom effect,
Consistency between the angle of view and the angle of sound collection is required. An example of the angle of view of the 10 × zoom lens is about 40 degrees at wide angle and about 4 degrees at telephoto. On the other hand, the sound collecting angle of the microphone is about 100 degrees at most even in the secondary sound pressure gradient type which is currently put into practical use as the sharp directivity, which is too wide as compared with the angle of view of the zoom lens. Therefore, there was no expected effect.

The latter stereo type microphone device audibly corrects the drawbacks of the above monaural type microphone device, and produces a natural zoom effect by adding information on the movement and direction of the object. .. The super-directivity that changes the sound collection angle of the left and right channels, the directivity main axis, and the sensitivity according to the angle of view of the camera, mainly focusing on stereo sound collection with wide presence at wide angle, and clearly collecting the target sound source at telephoto It mainly focuses on sex sound collection.
Similar to the monaural type microphone device, this microphone device is usually realized by synthesizing the outputs of a plurality of directional microphones (for example, Japanese Examined Patent Publication 6).
0-24636).

[0005]

However, since the conventional microphone device as described above uses a directional microphone such as unidirectional or bidirectional, as shown below, a video integrated camera is used. There was a problem in incorporating it into such devices.

Microphones are roughly classified into omnidirectional microphones and directional microphones, each having the following characteristics. An omnidirectional microphone has uniform sound pressure sensitivity frequency characteristics that do not depend on the direction, distance, and frequency of the sound source, and vibration sensitivity frequency characteristics that do not depend on frequency. On the other hand, in the directional microphone, the sound pressure sensitivity changes not only with the direction of the sound source but also with the distance. That is, when the distance between the sound source and the microphone approaches, the sensitivity in the front direction and the back direction increases in the bass range due to the so-called proximity effect. Further, its vibration characteristic also becomes high in the low frequency range. Further, the sensitivity in the low frequency range is similarly increased with respect to the wind.

From the above, first, in a sound collecting environment where ambient noise does not exist, it is generally advantageous that the microphone has a sharp directivity. However, when the distance between the sound source and the microphone becomes close, it is necessary to correct the proximity effect. Next, in a sound collecting environment in which a noise source exists near the microphone, for example, in a built-in microphone of a video-integrated camera, there are noise sources and vibration sources such as a drive system of a zoom lens and a tape running system. In such an environment and when the components of these noise sources are concentrated in the low frequency range, the omnidirectional microphone is more advantageous than the directional microphone. On the contrary, when the components of the noise source are concentrated in the high frequency range, the directional microphone is more advantageous than the omnidirectional microphone. Next, when wind is present due to outdoor use, the omnidirectional microphone is advantageous at least in the low frequency range.

As described above, in the case where a device such as a video-integrated type camera has a vibration source and a noise source inside and is used outdoors, a directional microphone is used as a constituent element. The conventional microphone device has a problem that the SN ratio of the sound pickup is lowered and the sound pickup quality is deteriorated. In particular, an attempt to sharpen the directivity over the entire sound range in order to improve the zoom effect is based on
There was a problem of decreasing the ratio.

In view of the above problems, the present invention is not only capable of picking up a zoom sound in synchronization with an image, but is also strong against noise such as vibration, proximity noise, and wind, and as a result, a video-integrated camera or the like. An object of the present invention is to provide a microphone device that can be incorporated in a device having a vibration source or a noise source inside as described above, and can reduce the size and weight of the entire device.

[0010]

In order to achieve this object, a microphone device of the present invention comprises first and second omnidirectional microphones which are arranged in a straight line at intervals. Connected to the first and second omnidirectional microphones and the third and fourth omnidirectional microphones, which are arranged in a straight line at intervals on the vertical bisector of the line segment connecting the second omnidirectional microphone A first high-pass filter, a second high-pass filter connected to a second omnidirectional microphone, first and second phase shifters connected to a third omnidirectional microphone, and A first subtractor that subtracts the output of the first phase shifter from the output of the first high-pass filter; and a second subtractor that subtracts the output of the first phase shifter from the output of the second high-pass filter. From the output of the fourth omnidirectional microphone A third subtractor for subtracting the output of the second phase shifter; a first equalizer for equalizing the output of the first subtractor; a second equalizer for equalizing the output of the second subtractor; A third equalizer that equalizes the output of the third subtractor, a third high-pass filter that cuts the low frequency range of the output of the third equalizer, and a first variable amplifier that varies the output of the first equalizer, A second variable amplifier that varies the output of the second equalizer; a third variable amplifier that varies the output of the third high-pass filter; and a first controller that controls the first and second variable amplifiers. A second controller for controlling the third variable amplifier, a first mixer for mixing the outputs of the first and third variable amplifiers, and a second mixer for mixing the outputs of the second and third variable amplifiers. It has a configuration of a mixer of 2.

[0011]

With the above-described structure, the present invention makes the low range omnidirectional and the middle and high range directional when the zoom signal is at a wide angle.
Since the low frequency range is cut off when the zoom signal is telephoto, it is resistant to noise such as vibration, proximity noise, and wind, and as a result, it has a vibration source and noise source inside, such as a video-integrated camera. Since it can be built into equipment, the overall size and weight of these equipment can be reduced. In addition, since the directivity of the mid-high range related to the sound image localization can be freely set by the time constant of the phase shifter based on the stereo sound collection, effective zoom sound collection is possible. Further, since the omnidirectional microphone is used, there is almost no variation in sensitivity, frequency characteristic, directional characteristic, etc., unlike a directional microphone, and a low-cost stable quality microphone device can be realized. Further, since the omnidirectional microphone is not greatly affected by diffraction unlike the directional microphone, it can be easily attached to a device. It is also possible to correct the influence of diffraction etc. by a circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a microphone device according to an embodiment of the present invention. In FIG. 1, 1 is a first omnidirectional microphone, 2 is a second omnidirectional microphone which is arranged in a straight line at a distance from it, and 3 is a first omnidirectional microphone 1 and a second omnidirectional microphone. The third omnidirectional microphones 4 arranged on the vertical bisector of the line segment connecting the directional microphones 2 are on the same vertical bisector and are spaced apart from the third omnidirectional microphone 3. The fourth omnidirectional microphone is arranged in a straight line. Here, the direction of the directional main axis of the center channel is from the third omnidirectional microphone 3 to the fourth omnidirectional microphone 4, which is the same direction as the directional main axis of the microphone device. Also, the direction of the directional principal axis of the stereo right channel is from the third omnidirectional microphone 3 to the first omnidirectional microphone 1, and similarly, the direction of the directional principal axis of the left channel of the stereo is It is in the direction from the third omnidirectional microphone 3 to the second omnidirectional microphone 2. If the angle of the directional principal axis of the microphone device viewed from the directional principal axis of the right channel is φ, the angle of the directional principal axis of the microphone device viewed from the directional principal axis of the left channel is −φ. d ₁
Is the distance between the third omnidirectional microphone 3 and the first omnidirectional microphone 1 and the second omnidirectional microphone 2, and d ₂ is the third omnidirectional microphone 3 and the fourth
Is the distance to the omnidirectional microphone 4. Reference numeral 5 is a first high-pass filter that receives the output V ₁ of the first omnidirectional microphone 1 and cuts a low frequency range, and 6 is the output V ₂ of the second omnidirectional microphone 2 that cuts a low frequency range. A second high-pass filter, 7 is a first phase shifter that receives the output V ₃ of the third omnidirectional microphone 3 and shifts by a phase shift angle θ ₁ , and 8 is an output V of the third omnidirectional microphone 3. _{A second} phase shifter that receives ₃ and shifts by a phase shift angle θ ₂ , 9 is a first subtractor that subtracts the output of the first phase shifter 7 from the output of the first high-pass filter 5, and 10 is a first A second subtractor that subtracts the output of the first phase shifter 7 from the output of the second high-pass filter 6, 11 is the output of the fourth omnidirectional microphone 4 V ₄ to the output of the second phase shifter 8. A third subtractor for subtracting 12
Is a first equalizer for equalizing the output characteristic of the first subtractor 9, 13 is a second equalizer for equalizing the output characteristic of the second subtractor 10, and 14 is equalizing the output characteristic of the third subtractor 11. A third equalizer 15, 15 is a third high-pass filter that receives the output of the third equalizer 14 and cuts the low frequency range. Reference numeral 16 is a first variable amplifier for varying the output level of the first equalizer 12, 17
Is a second variable amplifier that changes the output level of the second equalizer 13, 18 is a third variable amplifier that changes the output level of the third high-pass filter 15, and 19 is a zoom signal that changes from wide-angle to telephoto. The first controller 20, which controls the output levels of the first and second variable amplifiers 16 and 17 so as to be continuously attenuated in synchronism with, synchronizes with the zoom signal changing from wide angle to telephoto. A second controller 21 controls the output level of the third variable amplifier 18 so as to continuously increase, and a first mixer 21 mixes the outputs of the first and third variable amplifiers 16 and 18, Reference numeral 22 is a second mixer that mixes the outputs of the second and third variable amplifiers 17 and 18.

The operation of the microphone device configured as described above will be described below.

First, in the mid-high range that is higher than the cutoff frequency (fc) of the first high-pass filter 5 and the second high-pass filter 6, the first and second variable amplifiers 16 and 17 are provided.
The incoming input signals V _R1 and V _L1 have directivities about the directions of angles φ and −φ from the directivity main axis of the microphone device, and the directivity pattern thereof is as shown in FIG. In the low frequency range lower than the cut-off frequency (fc), the outputs V ₁ and V ₂ of the microphones 1 and ₂ are cut off, so that only the output V _{3 of the} microphone 3 is produced, and both V _R1 and V _L1 are omnidirectional. It becomes sex. Next, the input signal V _C1 entering the third variable amplifier 18 has a directivity which is the directivity main axis of the microphone device, and its directivity pattern is as shown in FIG.

The first and second variable amplifiers 16 and 17 are also provided.
Output levels V _R2 and V _L2 of the third variable amplifier 18 are controlled by the first controller 19 which receives the zoom signal, and the output level V _C2 of the third variable amplifier 18 is controlled by the second controller 20 which receives the zoom signal. , V _R2 , V _L2 , and V _C2 are as shown in FIG. 5, and in conjunction with the zoom signal changing from wide angle to telephoto, V _R2 and V _L2 are continuously attenuated and become minimum at the telephoto end.
On the contrary, V _C2 continuously increases and becomes maximum at the telephoto end. Finally, the output signal V _R2 of the first variable amplifier 16 and the output signal V _C2 of the third variable amplifier 18 are mixed by the first mixer 21,
The output signal V _R becomes the right channel output, the output signal V _{L2 of} the second variable amplifier 17 and the output signal V _C2 of the third variable amplifier 18 are mixed by the second mixer 22, and the output signal V _L Becomes the left channel output, and the directivity pattern of the output signals V _R and V _L of each channel changes from FIG. 2 to FIG. 3 to FIG. 4 in conjunction with the change of the zoom signal from wide angle to telephoto. .. In the figure, the solid line is the directivity pattern of the right channel, and the dotted line is the directivity pattern of the left channel. In this way, the camera signal is wide-directivity main axis of the output V _R, V _L of left and right channels phi, is open only -.phi, in conjunction with the camera signal changes to the telephoto, V _R, The directional main axis of V _L also gradually changes in the direction of the directional main axis of the microphone device, and at the telephoto end of the camera signal, the directional main axes of V _R and V _L become the same, and overlap with the directional main axis of the microphone device. The zoom sound can be picked up.

As described above, according to this embodiment, the low range is omnidirectional when the zoom signal is wide-angle and the middle and high ranges are directional, and the low range is cut when the zoom signal is telephoto. , Strong against noise such as vibration, proximity noise, wind,
As a result, it can be incorporated in a device having a vibration source or a noise source such as a video-integrated camera, and the size and weight of the entire device can be reduced. Further, since the directivity of the center channel and the directivity of the middle and high frequencies related to the sound image localization of each stereo channel can be freely set by the time constant of the phase shifter, effective zoom sound collection is possible. Further, since the omnidirectional microphone is used, there is almost no variation in sensitivity, frequency characteristic, directional characteristic, etc., unlike a directional microphone, and a low-cost stable quality microphone device can be realized. Further, since the omnidirectional microphone is not greatly affected by diffraction unlike the directional microphone, it can be easily attached to a device. It is also possible to correct the influence of diffraction etc. by a circuit. Also, as shown in FIG. 1, when the main axes of the four omnidirectional microphones are arranged in parallel and in the same direction and the four omnidirectional microphones are fixed so as to integrally vibrate, the directional of the center channel Sex area,
Also, in the mid-high range directional region of the left and right channels, the attenuation of the sound pressure sensitivity in the 90-degree direction with respect to the 0-degree direction with respect to each directional main axis is more advantageous than the omnidirectional vibration with respect to vibration. Become.

Although two phase shifters are used in this embodiment, the time constants of the two phase shifters are matched, the second phase shifter is deleted, and the first phase shifter is replaced by the first phase shifter. By connecting the outputs to the first to third subtractors, it is possible to ensure equivalent performance while rationalizing the circuit and reducing the cost. Also, a delay device may be used instead of the phase shifter.

Further, although the fourth omnidirectional microphone is arranged in front of the third omnidirectional microphone in this embodiment, the same result can be obtained even if the arrangement is changed as follows. That is, the fourth omnidirectional microphone is arranged in front of the first omnidirectional microphone at a distance of d ₂ , and the connection between the third omnidirectional microphone and the second phase shifter is deleted. , The output of the first omnidirectional microphone to the first
May be connected to the high-pass filter and the second phase shifter.
Alternatively, the same applies when the fourth omnidirectional microphone is arranged in front of the second omnidirectional microphone. This has the merit that when the microphone device is built in a device such as a video-integrated camera or an 8 mm camera, it can cope with changes in design in relation to other components.

[0020]

As described above, according to the present invention, the line segment connecting the first and second omnidirectional microphones and the first and second omnidirectional microphones which are arranged in a straight line at a distance from each other. , A third high-pass filter connected to the first non-directional microphone, and a second high-pass filter connected to the first non-directional microphone; Second connected to an omnidirectional microphone
High pass filter, first and second phase shifters connected to a third omnidirectional microphone, and first subtraction for subtracting the output of the first phase shifter from the output of the first high pass filter. And a second subtractor for subtracting the output of the first phase shifter from the output of the second high pass filter, and the output of the second phase shifter from the output of the fourth omnidirectional microphone. A third subtractor, a first equalizer that equalizes the output of the first subtractor, a second equalizer that equalizes the output of the second subtractor, and a first equalizer that equalizes the output of the third subtractor. A third equalizer, a third high-pass filter that cuts a low frequency range of the output of the third equalizer, a first variable amplifier that varies the output of the first equalizer, and a second
A second variable amplifier for varying the output of the equalizer, a third variable amplifier for varying the output of the third high pass filter, a first controller for controlling the first and second variable amplifiers, A second controller for controlling the output of the first and third variable amplifiers; and a second controller for mixing the outputs of the second and third variable amplifiers. With a mixer, the low range is omnidirectional when the zoom signal is wide-angle and the mid-high range is directional, and the low range is cut when the zoom signal is telephoto. Not only is it capable of producing sound, but it is also resistant to noise such as vibration, proximity noise, and wind. As a result, it can be built into equipment that has an internal vibration source or noise source, such as a video-integrated camera. Therefore, the overall size of these devices is
Weight reduction is possible. As described above, the present invention has great practical effects.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a microphone device according to an embodiment of the present invention.

FIG. 2 is a directivity pattern diagram at a wide-angle end of a zoom signal according to the same embodiment.

FIG. 3 is a directivity pattern diagram at an intermediate position between a wide angle and a telephoto of a zoom signal in the embodiment.

FIG. 4 is a directivity pattern diagram of a zoom signal at the telephoto end in the embodiment.

FIG. 5 is a change characteristic diagram of the output level of the variable amplifier in the embodiment.

[Explanation of symbols]

 1 1st omnidirectional microphone 2 2nd omnidirectional microphone 3 3rd omnidirectional microphone 4 4th omnidirectional microphone 5 1st high pass filter 6 2nd high pass filter 7 1st phase shift Device 8 second phase shifter 9 first subtractor 10 second subtractor 11 third subtractor 12 first equalizer 13 second equalizer 14 third equalizer 15 third high-pass filter 16 first Variable amplifier 17 Second variable amplifier 18 Third variable amplifier 19 First controller 20 Second controller 21 First mixer 22 Second mixer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimio Ono 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A first and a second omnidirectional microphones, which are arranged in a straight line at a distance from each other, and the first and the second.
Connected to the first and second omnidirectional microphones and the third and fourth omnidirectional microphones which are arranged in a straight line at intervals on the vertical bisector of the line segment connecting the omnidirectional microphones. The first high-pass filter and the second
Second high-pass filter connected to the omnidirectional microphone, first and second phase shifters connected to the third omnidirectional microphone, and the output of the first high-pass filter to the first high-pass filter. A first subtractor for subtracting the output of the first phase shifter; a second subtractor for subtracting the output of the first phase shifter from the output of the second high pass filter;
Third subtractor for subtracting the output of the second phase shifter from the output of the omnidirectional microphone, a first equalizer for equalizing the output of the first subtractor, and the second subtractor. Second equalizer for equalizing the output of the second equalizer, a third equalizer for equalizing the output of the third subtractor, a third high-pass filter for cutting the low frequency range of the output of the third equalizer, and the third equalizer. A first variable amplifier for varying the output of the first equalizer; a second variable amplifier for varying the output of the second equalizer; and a third variable amplifier for varying the output of the third high-pass filter,
A first controller for controlling the first and second variable amplifiers, and a second controller for controlling the third variable amplifier,
A microphone comprising: a first mixer that mixes outputs of the first and third variable amplifiers; and a second mixer that mixes outputs of the second and third variable amplifiers. apparatus. 2. The first, second, third and fourth omnidirectional microphones are arranged so that their main axes are parallel and in the same direction, and the first, second, third and fourth omnidirectional microphones are arranged. The microphone device according to claim 1, wherein the sex microphone is fixed so as to integrally vibrate.